Usage of gaseous fuel in various types of marine vessel is increasing due to its clean combustion and availability compared to e.g. heavy fuel oil or marine diesel oil.
Gas is typically stored in a tank or tanks in liquefied phase at low temperature. Typically the tank is filled so that there is always gas in liquid phase and gaseous phase, the liquid substance being below the gas in gaseous phase, which reserves a space in the upper part of the tank. Even if the tanks are insulated as such the heat losses cause natural evaporation of the gas increasing the pressure in the tank. There are also other possible reasons which might cause increase of pressure in the tank. In order to safely store liquefied gas in such a tank the tank is provided with a pressure relief valve fluidly coupled to the upper part of the tank.
It has been discovered that application of such a cryogenic tank in a marine vessels imposes special demands for the tank, in particular in respect to safety issues.
It is an object of the invention to provide a cryogenic tank arrangement and a marine vessel provided with the same, in which the safety of the tank arrangement is improved.